This invention relates to an electric float switch comprising an electric connection cable whose sheath surrounds current-carrying electric conductors that are insulated relative to each other, and which is sealingly connected to the casing of the switching device (float switch).
Since the sheath of an electric cable and the casing of an electric float switch have so far consisted of different materials as a rule, perfectly liquid-tight connections could only be accomplished at a considerable amount of technical equipment. This, however, entails the risk that leakage will be observed with respect to the ambient liquid after a certain period of service and the pull-off strength of the interconnected members will decrease.
As far as it is already known from printed publications that an electric cable with a sheath of polyurethane is connected by welding to an electric plug body consisting also of polyurethane, such welds do not remain impermeable to aggressive liquids in the long run and are therefore not suited for use as float switches, not to mention the fact that any special information cannot be found in these publications about the employed polyurethane that is available on the market in a great number of types.